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Hypocalcemia and impaired immune function are recognized risk factors for clinical disease in the transition period of dairy cows. At the onset of lactation, calcium homeostasis is disrupted by redirection of calcium for colostrum production, which triggers a substantial decrease in the blood calcium concentration for 1 to 4 days. Blood calcium concentration is associated with neutrophil function, which turn is associated with the risk of retained placenta, metritis, and mastitis. Negative Dietary CationAnion Difference (DCAD) diets fed during the prepartum period increase postpartum blood calcium concentrations and reduce the risk of disease. Our objectives were to assess the effects of a negative dietary cation-anion difference (DCAD) on phagocytosis (P) and oxidative burst (OB) function of circulating neutrophils and to determine the associations of serum ionized (iCa) and total calcium concentrations (tCa) with P and OB. We hypothesized that multiparous cows fed a negative DCAD prepartum would have greater serum ionized (iCa) and total calcium concentrations (tCa), and thus improved P and OB., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2019

El objetivo del presente estudio fue evaluar la relación entre producción de leche individual y fertilidad teniendo en cuenta el efecto contextual de rodeo. Para ello se utilizó una base de datos con 657.968 lactancias iniciadas entre 2001 y el 2012 en 677 rodeos de leche de la provincia de Buenos Aires, Argentina. La chances de que una vaca quede preñada a los 100 días en leche (DEL) fue evaluada con un modelo de regresión logística mixto (con dos niveles jerárquicos, el primero a nivel de la vaca y el segundo a nivel del rodeo). Las chances de preñez fueron explicadas por los predictores fijos producción individual de leche a los 80 DEL, número de parto, año de inicio de lactancia y estación de parto a nivel de la vaca, y con los cuartiles de la media de producción de leche a los 80 DEL a nivel de rodeo. En un rodeo de alta producción, las vacas que producen 1 desvío estándar (DE) sobre la media de su respectivo rodeo tuvieron una tasa de preñez a los 100 DEL 1,3 puntos porcentuales menor (31,4% vs 30,1%), pero si el mismo aumento en la producción individual de leche ocurre en un rodeo de baja producción las vacas más productivas aumentan 0,5 puntos porcentuales su chance de preñez a los 100 DEL (27,9% vs 28,4%). En conclusión, la relación entre producción de leche y performance reproductiva es estadísticamente significativa, pero los efectos biológicos son pequeños y varían dependiendo del nivel de producción del rodeo. The objective of the present study was to assess the relationship between individual cow milk yield and fertility, accounting for the contextual effect of the herd. A dataset including 657,968 lactations from 677 dairy herds located in Buenos Aires province Argentina from 2001 to 2012 was used. The odds of pregnancy by 100 DIMwere assessed by a multilevel logistic regression model (with cow as the first and herd as the second hierarchical level). Pregnancy by 100 DIM was explained with the fix predictors milk yield by 80 DIM, parity, year and calving season at cow level and quartiles of herd milk yield by 80 DIM as a herd contextual effect. Cows producing 1 standard deviation (SD) over the mean milk yield of their herd had 1.3 percentage point lower pregnancy by 100 DIM (31.4% vs 30.1%,) when in herds in the top quartile of milk yield, whereas they increased 0.5 percentage points (27.9% vs 28.4%) when in herds in the lowest quartile of milk yield.In conclusion, the relationship between milk yield and reproductive performance is statistically significant but the biological effect size is small,and it is modulated by herd production. Fil: Rearte, Ramiro. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: LeBlanc, S. J.. University of Guelph; Canadá Fil: Corva, S. G.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina Fil: de la Sota, Rodolfo Luzbel. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lacau, Isabel María. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Giuliodori, Mauricio Javier. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina

Disbudding is a common management procedure performed on dairy farms and, when done without pain mitigation, is viewed as a key welfare issue. Use of pain control has increased in recent years, but full adoption of anesthesia and analgesia by veterinarians or dairy producers has not been achieved. Part of the gap between primary research and application in the dairy industry may be driven by the lack of a consistent set of recommendations from primary research papers. Likewise, narrative reviews typically do not include evidence-based methods to identify, assess, and synthesize results; as a result, conclusions may suffer from bias. Conversely, properly conducted systematic reviews offer a more robust and transparent methodology to identify, evaluate, and summarize evidence on a given topic. Meta-analysis also allow for synthesis of overall effects as well as identification and exploration of causes of heterogeneity among studies, possibly identifying sources of variability that may be further examined or used to guide inferences of the robustness of the observed effects across different study designs or settings. The objective of this systematic review was to examine the effects of these pain control practices for the most common method of disbudding (cautery) on outcomes associated with disbudding pain in calves., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2018

Bovine respiratory disease (BRD) is an important illness of dairy replacement heifer calves that has substantial impacts on growth, survival and profitability. The objective of this research was to determine the effects of one or two doses of a commercial, multivalent, (MLV) vaccine, administered to heifer calves prior to weaning. It was hypothesized that vaccination would reduce the incidence of BRD and that two doses would be more efficacious than one., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2010

Colostrum feeding is an integral component of neonatal calf care with many effects on calf health and productivity, yet failure of passive transfer remains common on many dairy farms. A sufficient quantity and quality colostrum must be fed quickly to the newborn calf while minimizing bacterial contamination. Colostrum with a total bacteria count (TBC) >100,000 cfu/ml may impair IgG absorption and contribute to disease. Adenosine triphosphate ATP bioluminescence swabs offer a potential rapid calf-side alternative to traditional bacterial culture. The reagents in the swabs produce a light-generating reaction when in contact with bacterial ade¬ nosine triphosphate, which is quantified in relative light units (RLU) with a luminometer. The objective of this study was to validate the HygienaTM AquaSnap (AS), SuperSnap(SS), PRO-Clean (PC) and MicroSnap (MS) swabs as well as visual hygiene assessment for detection of elevated bacterial counts in or on colostrum-feeding equipment., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2017

The veal industry continues to have significant calf losses during the growing period representing a serious challenge to animal welfare and economic sustainability. As the majority of the mortality occurs in the first 21 days following arrival to veal farms, on arrival health status may be an important predictor of calf mortality. The objectives of this prospective case-control study were to describe the health status of male calves arriving at a veal farm and determine the risk factors associated with mortality in the first 21 days following arrival., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2017

Caustic paste disbudding is becoming more common-place in North America. A large body of work has examined pain control for cautery disbudding and surgical dehorning, but fewer studies have evaluated pain control for caustic paste disbudding, and results conflict regarding benefits of local anesthesia. In humans, the pain associated with a caustic, chemical burn can differ in nature, duration, and intensity compared to a thermal burn. The objective of this clinical trial was to evaluate the effects of either a lidocaine cornual nerve block or a topical anesthetic incorporated into caustic paste on the acute pain of caustic paste disbudding., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2017

The use of pain control for disbudding and dehorning is important from both an animal- and industry-centered perspective. Best practices include the use of local anesthetic, commonly given as a cornual nerve block, and a non-steroidal anti-inflammatory drug (NSAID). Approximately 40% of Canadian dairy producers do not use local anesthesia, perhaps in part due to lack of knowledge regarding cornual nerve block technique. Although this skill is typically learned in person from a veterinarian, alternative or adjunct methods may be useful for hard to reach producers. The objective of this trial was to determine if there were differences in the efficacy of online training, hands-on training, and a combined approach for teaching producers to successfully administer a cornual nerve block and disbud a calf less than 12 weeks of age., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2017

Animal care concerns, and thus animal care assessments have been increasing within the dairy industry. In Canada, a national Animal Care Assessment has just been implemented which utilizes animal based measures such as lameness and hock injuries. Veterinarians and producers in Canada agree that the top management issue on dairy farms is animal welfare and the number one health concern on dairy farms is lameness, and they agree that 'supporting animal health and welfare decisions' are major roles of the veterinarian. However, to date, there are no in depth qualitative publications investigating dairy producer's expectations on the role of veterinarians as advisors for animal welfare issues (i.e. lameness, hock injuries). The objective of this study was to explore dairy farmer’s perceptions of the role of the veterinarian as it pertains to communicating and consulting on animal care, and to gain insight into barriers that prevent animal care improvement through veterinarians., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2017

A large-scale observational study was conducted to estimate the within-herd prevalence and cow-level risk factors for ketosis in dairy cattle in herds that participate in a dairy herd improvement association (DHIA) program in Ontario, Canada., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2016

Although disbudding or dehorning dairy heifers is necessary for the safety of humans and other cattle, it has been identified as a key animal welfare issue when done without appropriate analgesia. Three-quarters of all disbudding or dehorning is done by dairy producers or on-farm staff, while the remainder is done by a veterinarian or veterinary technician. Reported use of pain control for these procedures by dairy producers ranges from 15 to 60%. Cautery disbudding is the most commonly used method; best practices include administration of a non-steroidal anti-inflammatory drug (NSAID) as well as local anesthetic given as a cornual nerve block (CNB). While NSAID administration is uncomplicated, CNB application requires technical training, which may limit use. Teaching methods have traditionally focused on one-on-one training with a veterinarian, although online disbudding training videos exist. To our knowledge, neither method has been studied for efficacy. Our objective was to determine if an online, interactive module could teach naive participants cautery disbudding technique, including CNB, as compared to hands-on training., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2016

Disbudding and dehorning (DD) dairy calves are common management procedures performed on-farm. Appropriate DD practices are important for the welfare of the calf, as well as public perception of the dairy industry. The objective of this study was to build on a 2004 survey of bovine veterinarians and dairy producers in Ontario to determine if DD protocols had changed over the past decade, and to examine factors associated with the adoption of pain-control practices., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2015

Timely diagnosis of pregnancy and pregnancy losses is economically important. A commercially available pregnancy-associated glycoprotein (PAG) milk assay (IDEXX Laboratories, Inc.) is offered through routine Dairy Herd Improvement (DHI) testing for diagnosis of pregnancy. The objective of this observational study was to describe the relationship between PAG at various stages of gestation and the likelihood of successful calving. The hypothesis was that higher PAG levels would be associated with successful calving., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2015

Many options are available to dairy producers for managing reproduction in their herds. Reproductive performance varies greatly among farms, but the reasons for this are not well described. The objective of this study was to identify management practices associated with reproductive performance on Canadian dairy farms., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2015

The dairy industry in the developed world has undergone profound changes over recent decades. In this paper, we present an overview of some of the most important recent changes in the dairy industry that affect health and welfare of dairy cows, as well as the science associated with these changes. Additionally, knowledge gaps are identified where research is needed to guide the dairy industry through changes that are occurring now or that we expect will occur in the future. The number of farms has decreased considerably, whereas herd size has increased. As a result, an increasing number of dairy farms depend on hired (nonfamily) labor. Regular professional communication and establishment of farm-specific protocols are essential to minimize human errors and ensure consistency of practices. Average milk production per cow has increased, partly because of improvements in nutrition and management but also because of genetic selection for milk production. Adoption of new technologies (e.g., automated calf feeders, cow activity monitors, and automated milking systems) is accelerating. However, utilization of the data and action lists that these systems generate for health and welfare of livestock is still largely unrealized, and more training of dairy farmers, their employees, and their advisors is necessary. Concurrently, to remain competitive and to preserve their social license to operate, farmers are increasingly required to adopt increased standards for food safety and biosecurity, become less reliant on the use of antimicrobials and hormones, and provide assurances regarding animal welfare. Partly because of increasing herd size but also in response to animal welfare regulations in some countries, the proportion of dairy herds housed in tiestalls has decreased considerably. Although in some countries access to pasture is regulated, in countries that traditionally practiced seasonal grazing, fewer farmers let their dairy cows graze in the summer. The proportion of organic dairy farms has increased globally and, given the pressure to decrease the use of antimicrobials and hormones, conventional farms may be able to learn from well-managed organic farms. The possibilities of using milk for disease diagnostics and monitoring are considerable, and dairy herd improvement associations will continue to expand the number of tests offered to diagnose diseases and pregnancy. Genetic and genomic selection for increased resistance to disease offers substantial potential but requires collection of additional phenotypic data. There is every expectation that changes in the dairy industry will be further accentuated and additional novel technologies and different management practices will be adopted in the future.

Individual and herd ketone levels are commonly monitored in dairy cattle post-partum to identify individuals at-risk of metabolic disease and to identify potential improvements to management factors. The Precision Xtra handheld meter has been validated for use for β-hydroxybutyrate (BHBA) measurements post-calving as a convenient cow-side test for ketonemia. Recent research has identified BHBA cut points prepartum associated with increased risk of post-partum disease, but at much lower cut-offs than those indicating hyperketonia after calving: 0.6 to 0.8 mmol/L in comparison to 1.0 to 1.4 mmol/L. The objective of the current research is to validate the handheld device, Precision Xtra, in the measurement of BHBA in whole blood against the gold standard method, laboratory evaluation of serum, to assess its diagnostic accuracy in detecting BHBA pre-calving in the range of 0.6 to 0.8 mmol/L., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2014

Many dairy herds do not achieve their targets for reproductive performance. Despite many advances in technologies and management tools, producer attitudes towards, and frequency of implementation of these tools are not well documented. The objective of the present study was to survey current reproduction management practices in a representative sample of Canadian dairy farms., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2014

The incidence rate of left displaced abomasum (LDA) in North America is commonly 3 to 7% of calvings. Of these cases, 12 to 17% are culled or die within 30 days of surgery. There have been numerous studies focused on predicting prognosis for right displaced abomasal corrective surgery; however, fewer studies focus on LDA surgeries. These studies tend to measure only a few parameters (i.e. blood analysis) and none focus on concurrent disease or physical exam at diagnosis. Croushore et al (2013) reported that cows that were not ketotic at diagnosis (BHBA, American Association of Bovine Practitioners Proceedings of the Annual Conference, 2014

The determinants of metabolic and reproductive health disorders and the degree to which housing and management can influence health are only partially understood. The objective of this randomized controlled study was to determine if a prepartum housing strategy of providing non-competitive feeding and lying access improves metabolic health and immune function and reduces reproductive disease., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2014